<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="./plugin/css/perfect-scrollbar.min.css">
    <link rel="stylesheet" href="./plugin/css/prettify.css">
    <script src="../jquery-3.1.1.min.js"></script>
    <script src="./plugin/js/perfect-scrollbar.min.js"></script>
    <script src="./plugin/js/prettify.js"></script>
    <style>
        #container{
            height:100px;
            width:100px;
            /*overflow-y: scroll;*/
            /*overflow-x: hidden;*/
            overflow: auto;
            margin: 0 auto;
            position: relative;
        }
        .content{
            height:400px;
            width: 100px;
            background:linear-gradient(to top, white, black);
        }
    </style>

</head>
<body>
    <div id="container">
        <div class="content"></div>
    </div>
    <script>
         Ps.initialize($('#container').get(0));
    </script>
</body>
</html>